Testing machine



March 4, 1930. s. N. SENNA TESTING MACHINE Filed June 18, 1928 INVENTOR.

A TTORNEY' i jparts constituting the invention which for 'P a tentedMar. 4, 1930 smear N: 'snri m; or;p. ir;n; or'nn;v ASSACHUSETTS;AssIeNoR T is. F; PERKINS &

- .son,'1no.,'-or HoI-ivo E, AssncnUsn rTs, naoonronsrrronorMASSACHUSETTS vices for-fuse inconnectionw'ith machines for i 7 whichis? distended bya fluid "through the ifs'p'ecimen' -platform anapertured clamp for ma t ti G INE. i

' I 'This invention relates to improvements-in t ting machines and isdirected particularly 'to' improvements int specimen clamping testingthetensile strength of paper andthe' 21. A well-known form ofmachine fortesting paper and the likewcomprises. an apertured 'clamping a; specimentofithe platform and a yieldable diaphragm below the platform,

aperture 'therein to distend andfrupture the specimen; 4 the pressure}offthe liquid at the time of rupture being] read on a gauge "and jacentfaces thereof are substantially smooth and non-yieldable so that inorder to .hold'the than would'b-e the case if "not so: injured.According to the principal object of this specimen against movementduring the test ployed. This pressure subjects the specimen thereof andit is often ruptured the diaphragm more readily orat a less pressure thespecimen was I invention Iprovide a, novel clampingmeans in connectionwith apparatus. of the class described whereby the .specimenis held forthe distending thereof without the excessive pressure referred tosothatthe consequent I injury is, obviated and an accurate test obtamed-This is accomplished means of p v with, and

the, novel combination andjarrangement of purposes of disclosurev willbe I described in the form at present preferred and which is In, thedrawings:

Fig.1 isa small scale side elevational view of one form of atesting-machine having the features of' the invention associated there-Fig. 2 is a partial elevational' View at a Referring now to the drawingsin detail the inventionwill be described. A testing (7 machine of thetype referred to is represented at T Whichjhasa fluid chamber F and apisitfon reciprocahle therein to force a liquid 1n the'chamber against ayieldable diaphragm 'D' which is'clampe'd to the upper side of the'chamher by a-platform or specimen support .S A rod Rin threadedengagement with theY'upp'e'r endof theframe ,of' the machine is providedwith a hand Wheel Hfor rotating the'same and which on its lower endcarries aspecimen clampingmember C. The structure ust describedisgenerally old in the art "aridFWiIl'no't be" gone into in detail. Thepurpose of the clamp C is to clamp a speci- "menof paper'or the like tothe support S so that the diaphragm maybe distended by the fluid torupture the specimen While it is so held. The press'ureof the liquidat't-he in- ";s'taiit of rupture is usually recorded by a gauge-which isrepresented at G, which pressure is taken as the designation of thestrength of 'the jspecimen.

As 'has'been previously stated it is usual to provide the ring-likeclamping member C and theupper side of the apertured platform stantiallysmooth specimen olamp- S with su ing-surfacesi Since these parts-are ofmetal .there'results non-yieldable hard surfaces for clamping of thepaper and in order that the 1 specimen may be securely clamped by thesurfaces which are smooth and hard, it is of a course obvious that'anexcessiveor at least a considerable clamping pressure must be applied.This tends to injure the specimen,

and in thei'case of paper is likely to break thefibers thereof, so thatthe specimen actuallyruptures' at a less'pressure than it should.Itfwill be; noted that since the specimenis distended iupwardly throughthe platform and--clamp by'- the diaphragm that it'is of courseelongated to some extent and that-also forbest results it is desired toclampthe specimen'firmly about jthe central; portion whichiis tobedistended and finally'ruptured.

P-Accordingto the novelfeatures of my invention for firmly clamping thespecimen I providein the upper face of the supporting platform S aroughened portion about'the aperture therein. This may be accomplishedin one way bylmurling the said surface or by cutting concentricgrooves10 in a spaced relation therein. To co-operate with this roughenedsurface I secure to the clamp a resilient' or yieldable 'ringlikeclamping member in the, form of a pad 12 which m'ay'be'off rubber orsome other suitablematerial. I This;

pad 12 is preferably ringlike as described to provide an aperturetherethrough to correspond with the'apertures in the platforman'd clampC and may be secured to the lower side of the clamp by any convenientmanner. In operation by means of the novel features described, thespecimen is pressed'against"'the roughened surface ofthe'plat form S theriiiglike yieldable pad in the shown in Fig.2, and it will be noted thatthe yieldable clamping pad forces the specimen at least partly into thegrooves .Jof the vplatform; LSO that as pressure is applied to the underside of thefspecimen by the; fluid actuated; diaphragm it is securelyheld around 'tlie' aper; ture against a relative movement with respecttothe platform andi'clamp'. By reasonlof the novel combination: ndarrangement o.f parts shown and described, the spec men s not onlyfirmlyheld against displacement forthe testingv operation, but thecoTasting, clamping members do not tend toinjure or disruptf he fibersof the specimen wherebyitis not likely to be ruptured in testinguntiltheextreme pressure at which it will rupturehasbeen attained. I

By means of the novel featuresof the indiaphragm below said P m, a clampsaid central opening and the'saidclamp being provided with a ring-likeyieldable clamp- 'movable towards and away from said platform, thesupporting surface of said platform" j V being substantiallynonyieldable and pro; 1

vided with concentric grooves disposed about 3 ing memberdisposedthereonso as to overlie I the grooves of said platform andco-operate therewith forclamping a specimen thereto. '3. A machine ofthe "class described com- .clamped therebetween by being qrcaaintp theepres ant: byftheyieldeblesurface. M 4. machine, ofthe classeescribedcomprising in combination, a platform member for supporting a specimenhaving-a central I, opening, a 'yiel-da'ble diaphragm below said;platform, a clamp 'memberln'ovable towards f):

and away-from said platform, the surface of;

one of said members being .nomyieldable and providedwith depressionsabout the central" opening therein and the other member being i provided:with a ring like clamping. member ldab a e l PQ e -iher w so? to overliethe ,depressionsof the other memyy;

ber for co-oiperating f ie i withg 'aspecimen.

vention it is possible to obtain, more {accurate tests than have beenpossible heretofore and specimens of varying thicknesses byreason oftheyieldable characteristics oifthe clamp are clamped firmly andproperlyfor'the test--.

ing operations.

I am aware thatmanychangesmay be made inthe formof the inventionwithbutdeparts ing from the spirit and scope thereofandl prefer therefore to belimited, if at all, by the appended claimsrather than by the foregoing Idescription.

WhatI'claimisjz' e, 1. A machine of the class. described comprising incombination, a platform member having a specimen supporting surface andacentral aperture therethrough, a,:cla'mp member having a specimenengaging'surface and v a central aperture therethrough the surfaces ofsaid members. beingrel'ativelyi.yie'ldabl'e and jno'n-yiel'dable and oneof said surfaces 7' I being provided with depressions whereby a specimenmay be forced thereinbytjheother Y surface. v v V. .7

2. A machine ofthe class described tcomprising in combination, aplatform for supporting a specimen having a central opening therethroughfor receiving a diaphragm, a

